The present invention relates to agricultural implements, and particularly to larger agricultural implements adapted to be pulled behind modern tractors and which take advantage of the larger horsepower of such tractors and are therefore quite wide in use. By way of example, the invention is described in the embodiment of a planter having 24 or more individual planter row units and which will extend 75 feet or more in use.
One important consideration of such large implements is the mode and manner in which it is transported. Obviously, such an implement cannot be transported to and from the field over roads in the same position or configuration in which it is set up for field use. Some early planters required separate transport trailers. In addition to the cost for the special-use transport trailers, such systems were limited in length by the practical requirements of having to load the implement on the trailer and to unload it. In addition, considerable time is consumed in loading the implement on the trailer to transport it to a second field, and to then set up the implement in the new field. This time can be considerable especially when related to the short time normally available when good planting conditions prevail.
Other attempts to provide larger implements included folding vertically the outer ends of the frame or bar on which the row units are mounted. These structures may be acceptable for cultivators and the like, but there is a limitation on the height of the implement for getting it through gates and into sheds. In the case of a planter, these implements have the disadvantage that the lids of the hoppers turned on their sides may come loose thereby spilling seed or insecticide. Other folding configurations include one which folds the outer portions of the mounting bar rearwardly, leaving the center portion fixed. Again, limitations are imposed on the length of these implements and there are disadvantages in converting them between use and transport conditions.
A significant improvement in planter design was effected by the system disclosed in my U.S. Pat. No. 4,117,893. This system which has proved commercially successful, permits the planter bar to fold about its centerline, and links are used to lock the two side sections or wings either in the use position in which the mounting bars are aligned and transverse of the direction of travel of the tractor, or in the transport position, in which the mounting bars for the two sets of row units are folded rearwardly and are parallel to the direction of travel of the tractor. This system proved successful because it was capable of being converted between the use and transport position by a single operator without having to leave the tractor, and because it enabled planters of 16 or 18 and even 24 row configurations to be designed. Such larger planters are desirable, particularly by operators of larger acreage where, as mentioned, the time during which ideal planting conditions exist, is short.
Another folding tool bar is disclosed in U.S. Pat. No. 4,137,852, in which the center section of the planter bar remains fixed in both the transport and use configurations, but the end sections fold forwardly by means of an hydraulic mechanism. This system has the disadvantage that the draught or tongue section of the implement is required to be very long to accomodate the forwardly-folding planter bar sections, but in use, the length of the tongue section becomes a disadvantage because it reduces the ability of the operator to maneuver the combination of tractor and implement.
The present invention presents a uniquely different approach to a large implement by permitting the main frame to be "rigid" in the sense that it does not fold for transport, but is provided in articulated sections to flex in order to follow ground contour). The implement is transported from the side. This is accomplished by a hitch structure having two draught members or tongues which are pivotally connected to the main frame which is sometimes referred to as a "carrier" because the tool sections are supported by it. One of the draught members (sometimes referred to as a control link) is connected to the tractor hitch, and it remains connected to the tractor hitch in the use position, the transport position, and intermediate positions when the implement is being converted between use and transport.
In the use position, the forward end of the other draught member is locked to the forward end of the control draught member to form a rigid triangle with the carrier frame, thereby maintaining the carrier frame transverse of the direction of travel of the tractor in the desired use position.
When it is desired to convert the implement to the transport position, the operator actuates a hydraulic cylinder from his station on the tractor, and the cylinder unlocks the second draught member from the control draught member so that the second draught member is free to pivot. The operator then drives the tractor around to the side of the implement, preferably the left side of the implement so that any commodity or supply transported by the forward part of the carrier frame during use will overhang the shoulder of the road during transport and not interfere with oncoming traffic. As the tractor moves from the front of the implement frame to the side, it rotates the control draught member to control the steering mechanism for the support wheels of the implement. This control member thus has two functions, one of which is to transmit force from the tractor to the carrier frame in both the use position and the transport position, and its other function is to control the steering of the support wheels.
In use, the steering mechanis steers the carrier frame support wheels in the forward direction. As the control draught member is rotated to the side to convert the implement for road travel, it rotates the support wheels 90.degree. so that they now face to the side. The same wheels are thus used to transport the carrier frame over the road as were used to support it in field use. Further, in transport, the same steering linkages are responsive to the turning of the tractor which, in turn, rotates the control link, to steer the support wheels to provide great maneuverability for such a large implement. The forward support wheels are steered in the direction the tractor turns, whereas the rear support wheels (the right side support wheels in the use position) are steered in a counter direction to bring the right end of the carrier frame around the turn.
As used herein, the term "front" refers to the front of the implement as it is set up for use and facing the direction of travel of the tractor. Similarly, the left and right sides of the implement correspond to the left and right sides of a viewer looking in the direction of travel. These conventions are not changed even though the implement may be set up for transport. Thus, the left side of the implement in transport is still referred to as the left side, not the "front" even though it precedes the right side of the implement of the illustrated embodiment when it is being transported.
In the illustrated embodiment, a very large planter is disclosed having four sets of dual wheels for supporting the implement. Two sets of dual wheels support the left side of the implement and two sets support the right side. There is also a transport wheel mounted to the rear of the frame, and it is lowered for transport. The transport wheel is not a steerable wheel so that in the transport mode, the entire implement pivots about the transport wheel as the tractor turns. Moreover, in the illustrated embodiment, the outboard sets of steerable wheels are turned at greater angular displacements than are the inboard sets to facilitate maneuvering the very large implement.
Another consideration of large implements of this type is the cost involved in manufacturing the main carrier frame. There is a desire to make the main frame heavy, particularly in the case of ground working tools so that that weight can be transferred from the frame to the tools during working. However, weight and bulk add expense, and in conventional designs where each large implement has its own frame, adding weight to the main frame has the disadvantage of adding cost to each implement. By providing separate frames for each large implement, the cost increase is exacerbated since many items such as support wheels, folding and transport mechanisms, hitch assemblies, hydraulic lines and controls, and so on, are actually duplicated. Thus, the overall expense to the farmer is ultimately increased greatly.
The present invention provides a large carrier frame which can be made, and in fact is, quite massive. Because of the size of the frame, it is provided in separate sections with adjacent sections connected to each other so that they can pivot about a horizontal axis parallel to the direction of travel of the vehicle. This enables the implement frame to flex and to follow more closely the contour of the ground.
For each carrier frame section, there is provided a corresponding tool section or subframe on which the tools are mounted. This subframe establishes the lateral spacing and operating depth of the tools. Each tool subframe is mounted to its associated main carrier frame section by two forward pivots and an hydraulic cylinder similar to the three-point hitch on a tractor. The hydraulic cylinder may be actuated from the operator's station to separately lift the entire tool section independently of other tool sections. This feature facilitates the working of point rows. Further, in the case of a planter, the subframe also carries the drive pick-up wheel which supplies drive power to the meters of the individual planter row units. By lifting the entire planter subframe, the drive wheels are also raised so there is no need to disengage the drive in converting the system to the transport position or in turning around in the field. In prior systems, the meter drive wheels have been mounted to a single main frame, thereby requiring either that the meter drives be disengaged or that the main frame be raised for transport.
Each tool section further has its own depth gauge means which, in the case of a planter, is provided in the row units themselves. Thus, the carrier main frame does not have to have hydraulic cylinders for raising it. It can remain at a fixed height. Any hydraulic cylinders for raising the main frame would be quite large and therefore expensive. The carrier frame can also be used to store centrally large quantities of commodities or supplies which need not be raised. Further, each tool section can be replaced by a different tool section for performing a separate function. Thus, the carrier frame and its attendant structure, support wheels, hydraulic controls, and the like, can be used for different farming functions, such as planting, cultivating, chisel plowing, fertilizer application, spraying herbicide, and many others. The individual tool sections can be stored in a smaller space.
Other features and advantages of the present invention will be readily apparent to persons skilled in the art from the following detailed description of a preferred embodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts of the various views.